Longitudinal Follow-Up and Outcomes for Chinese Patients with Stage 1–4 Chronic Kidney Disease

Abstract

<b><i>Introduction:</i></b> Understanding heterogeneity in the prognosis of chronic kidney disease (CKD) has implications in management of patients. We aimed to evaluate the comparative risk of end-stage kidney disease (ESKD), cardiovascular (CV) events, and death among patients with CKD in China. <b><i>Methods:</i></b> In total, 3,700 patients with CKD stage 1–4 were recruited from 39 clinical centers in China between 2011 and 2016. New occurrence of ESKD, CV events, and all-cause mortality was recorded until the end of 2017. The crude incidence rate was calculated for each outcome. Ratios of incidence between different outcomes were generated with 95% confidence interval (CI) estimated by 1,000 times of bootstrapping. Multivariable adjusted Cox regression models accounting for competing risk between the outcomes were used to evaluate the association of risk factors with the outcomes. <b><i>Results:</i></b> The population mean age was 50 ± 14 years, with 58.2% male and 60.3% of glomerulonephritis. After a median follow-up of 4.65 years (interquartile range [IQR]: 3.71–5.60 years) for ESKD, 4.76 years (IQR: 3.97–5.76 years) for CV events, and 4.84 years (IQR: 3.97–5.76 years) for death, the incidence rates of the 3 outcomes were 3.1, 1.5, and 0.92/100 patient-years, respectively. The ratio for the incidence of ESKD and CV events was 2.15 (95% CI: 1.87, 2.53) and that for incidence of ESKD and death was 3.41 (95% CI: 2.88, 4.08). Significant differences regarding the ratios were detected through levels of age, history of CV disease, the estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (uACR), and etiology of CKD. In the Cox regression model adjusting for traditional CV and kidney-specific risk factors, older age was associated with a higher risk of CV events and death but a lower risk of ESKD (hazard ratios [HRs] = 1.45 [95% CI: 1.29, 1.64], 1.48 [95% CI: 1.29, 1.70], and 0.78 [95% CI: 0.73, 0.84] per 10 year increase, respectively). By comparison, reduced eGFR was associated with a higher risk of ESKD and death, rather than CV events (HRs = 3.62 [95% CI: 2.96, 4.43], 1.30 [95% CI: 1.02, 1.66], and 1.22 [95% CI: 0.99, 1.49] per 30.26 mL/min/1.73 m² increase, respectively). Similar patterns were seen for increased uACR (HRs = 1.42 [95% CI: 1.30, 1.55], 1.17 [95% CI: 1.05, 1.30], and 1.07 [95% CI: 0.99, 1.17] per 1 natural log-transformed value increase, respectively). <b><i>Conclusion:</i></b> ESKD was more likely to occur than CV events and death in the population with CKD stage 1–4 in China. Traditional risk factors contributed differently to the comparative risk of the outcomes.